EFnet announced that the server (eris.Berkeley.EDU) that caused the original IRC network to split back in 1990 ("The Great Split") has rejoined the network. Because of this EFnet (Eris-Free Network) changed its name to "Eris Network", or ErisNet.
eris.Berkeley.EDU is once again serving IRC clients (on ports 6667, 6668 or 6697, 9999 for SSL), thanks to UC Berkeley OCF.
See the news post about this change on http://www.erisnet.org/erisnet_pressrelease.pdf [erisnet.org]